1. Field of Invention
This invention relates to a development system for creating color output images in a printing machine.
2. Description of Related Art
High-end printing includes not only process color, i.e., color produced by overlapping halftone patterns of cyan, magenta, yellow, and/or black inks), but also customer-selected spot colors. Customer-selectable color printing materials, including print media, printing inks and developing materials, can be manufactured by determining precise amounts of constituent basic color components making up a given customer-selectable color material, providing precisely measured amounts of each constituent basic color component, and thoroughly mixing these color components. This process is commonly facilitated by reference to a color guide or swatch book containing hundreds or even thousands of swatches illustrating different colors, where each color swatch is associated with a specific formulation of colorants. Probably the most popular of these color guides is published by Pantone(copyright), Inc. of Moonachie, N.J.
Offset and gravure presses print solid layers of these mixed colorants to match the customer-selected color specified by a Pantone(copyright) number. Printing solid layers of inks mixed from a large set of primaries has several advantages over process color printing. For example, many colors can be produced which are outside the color gamut of process color printing. More precise color control and matching is possible with a large set of component colors, since often, a component color is close to the customer-selected color. Additionally, there are fewer sources of color variation with a large set of component colors than there are in a color produced by overprinting several separate colors. Also, fine lines and fonts appear smoother when printed as a solid ink layer than as a halftone pattern. Still further, the solid ink layer resulting with a large set of component colors will appear less grainy than a halftone pattern. Because of the importance of customer-selected color to high-end printing, the color management systems for both a Windows(copyright) and Macintosh(copyright) operating system provide processes for specifying customer-selected colors by number, and for passing this information to printers. Similarly, all major personal computer graphics software packages which can output color information directed to preparing printing plates provide methods of specifying Pantone(copyright) colors.
Customer-selectable spot color is especially important in wallpaper and fabric printing. In these areas, halftoning and process color are uncommon. Instead, all colors are produced by spot colors. A wallcovering, for instance, may have eight colors in its pattern, printed by eight gravure rolls, each containing a separate spot color.
Currently, customer-selectable spot color processing methods involve a human operator mixing customer-selected inks according to predetermined formulas, such as those provided by the Pantone(copyright) CMS. In various exemplary embodiments, these formulas specify weight fractions of each component to be combined to make the customer-selected color. The human operator weighs out the component inks and combines them by hand. Typically, the combination is done with a spatula, on a marble slab. Because printed color depends on both the inks used and the substrate on which they are printed, the human operator will frequently deposit a draw-down layer of ink on the target substrate and a make a visual comparison to the customer-selected color.
Computer mixing systems also exist that direct the above steps and calculate each ink adjustment based on tristimulus value differences (xcex94X, xcex94Y, xcex94Z) between a current color and a target color, as disclosed by Z. W. Wicks, et al. in Journal of Coatings Technology, Vol. 73, No. 918, July 2001. However, Applicants are unaware of a system that automates color mixing in the print engine.
In view of the conventional techniques discussed above, new systems and methods for integration of customer-selectable ink mixing with a computer control system and an automated printer are desirable.
This invention separately provides systems and methods that create colorant mixtures based on a number of target colors, where the target colors may be one or more colorants, per se, or a medium colored by or printed using one or more colorants.
This invention separately provides an ink supply station including a color control computer program, an ink mixing station, and, optionally, cleaning and waste disposal stations integrally connected to a print engine.
This invention separately provides systems and methods for efficiently using a colorant supply and mixing system to produce color matches for a plurality of target colors in an order which optimizes colorant usage.
This invention separately provides systems and methods for efficiently scheduling color matching of target colors to optimize the accuracy of color matches.
This invention separately provides systems and methods of efficiently using a limited number of colorant containers to accurately match target colors using a number of colorants which exceeds the limited number of colorant containers.
This invention separately provides systems and methods of accurately matching a number of target colors by integrating mixing of colorants similar to the Pantone(copyright) primaries with a computer color controller and print engine.
This invention separately provides a method of automating the mixing of component colors to match a customer-selected color.
This invention also includes methods for automating the emptying, cleaning, and refilling of the mixed colorant supply chamber when the customer-selected color changes.
This invention separately provides an ink supply station which accepts a color specification from the print engine""s control system, automatically mixes a combination of colored inks to match a customer-selected color, and delivers the mixed colorant to the print engine.
In various exemplary embodiments of the systems and methods according to the invention, the ink mixing station can accommodate two or more containers of component colors, as well as optional dispersants and other ink components. The ink mixing station also includes an ink supply chamber in which the component colors are mixed, valves and connectors for adding the components to the ink supply container, a connector for supplying the ink to the print engine, and, optionally, a connector to return unused ink to the ink supply container.
In various exemplary embodiments, the color control computer program takes as input a customer-selected color, such as, for example, a color specified by the Pantone(copyright) Color Matching System, to be printed by the print engine and outputs signals to the ink mixing station which cause mixing of component colors to be mixed to make a mixed color matching the customer-selected color. The systems and methods of this invention may optionally include waste disposal and /or cleaning stations. The ink supply station according to this invention may automatically empty and clean the mixed colorant supply chamber.
In various exemplary embodiments of the systems and methods according to the invention, an ink mixing system, and the print engine are controllably integrated in a way that is unlike any method used in the offset, gravure, flexographic, dry xerographic, liquid xerographic, or ink jet printing fields. The systems and methods according to the invention also include novel color changing methods and novel methods to utilize and exploit certain substrate properties, beyond the conventional methods used to control colorant mixing.
In various exemplary embodiments of the systems and methods of this invention, the ink supply station provides a mixed colorant whose color matches a customer-selected ink color. In various exemplary embodiments of the systems and methods of this invention, the ink supply station provides a mixed colorant which, when printed on the customer-selected substrate, matches the customer-selected printed color. The ink supply station includes a color controller program and an ink mixing station. The color controller receives as an input a customer-specified color. The color controller directs the ink mixing station to mix component colors in specific amounts, resulting in the customer""s specified color.
The systems and methods according to the invention encompass any kind of ink and/or printing media or substrate which may be combined and printed, and all kinds of print engines which may use these mixed colorants to match customer-selected colors. While this invention explicitly applies to the mixing of color marking materials for lithography, offset lithography, gravure, flexography, silk screen, letterpress printing ink jet printing and to the mixing of liquid or dry xerographic toners for ionographic or xerographic printing, it should be appreciated that computer-controlled mixing to match customer-selected colors according to this invention can be used with other types of colorants or color marking materials and/or printing media or substrates and methods, and the like. Accordingly, when the application refers to inks, it is to be understood to refer to any type of colorants or color marking materials.
These and other features and advantages of this invention are described in or are apparent from the following detailed description of the preferred embodiments.